Quick Answer
Retina is a 3 to 4 question topic per NEET PG paper. Lock these:
- RRD symptoms — flashes, new floaters, curtain shadow. Risk: myopia, aphakia, trauma, lattice, PVD.
- TRD — PDR is the top cause; also sickle cell retinopathy, ROP.
- ERD — no break; Coats disease, tumours, VKH, malignant hypertension.
- PVD with Weiss ring — 10 to 15 percent harbour a retinal tear; dilated exam within 2 weeks.
- Retinal tear — barrier laser retinopexy within 24 to 72 hours.
- Wet AMD — anti-VEGF (ranibizumab, aflibercept, bevacizumab, brolucizumab, faricimab).
- Dry AMD — AREDS2 vitamins slow progression in intermediate stages.
- DME — anti-VEGF first-line; OCT for thickness; steroid or laser adjuncts.
- CRAO — cherry-red spot; ocular massage, AC paracentesis, acetazolamide, carbogen; rule out GCA in over-50s.
- CRVO — blood-and-thunder fundus; anti-VEGF for macular edema.
- Retinitis pigmentosa — night blindness, bone-spicule pigmentation, ring scotoma, ERG diminished.
- CSCR — young stressed male; steroid link; observe or PDT if chronic.
Retinal disorders sit at the intersection of anatomy, physiology, and pharmacology — and examiners love them for exactly that reason. This deep dive covers the detachment triad, posterior vitreous detachment, macular disease (AMD, DME, CSCR), vascular occlusions and retinitis pigmentosa, with an eye to India-specific epidemiology.
Retinal anatomy essentials
The neurosensory retina has ten layers, from vitreous side to choroid — internal limiting membrane, nerve fibre layer, ganglion cell layer, inner plexiform, inner nuclear, outer plexiform, outer nuclear, external limiting membrane, photoreceptor layer, retinal pigment epithelium. The macula is a 5.5 mm diameter oval centred on the fovea; the foveola (0.35 mm) is avascular and cone-rich. The peripheral retina is rod-dominant. Vascular supply is dual — the central retinal artery supplies the inner retina; the choroid nourishes the outer retina and photoreceptors by diffusion through Bruch membrane and the RPE.
Retinal detachment — the three types
Rhegmatogenous retinal detachment (RRD)
The commonest type. A full-thickness break lets liquefied vitreous track into the subretinal space.
- Risk factors — high myopia, previous cataract surgery (especially with vitreous loss), ocular trauma, lattice degeneration, family history, posterior vitreous detachment.
- Symptoms — photopsia (flashes, from vitreous traction on retina), new floaters (spider web, cobweb), curtain-like shadow progressing across the visual field, vision loss when the macula detaches.
- Signs — a corrugated, mobile detached retina with a visible break (horseshoe tear, round hole or dialysis); Shafer sign (pigmented cells in the anterior vitreous).
- Investigations — dilated fundus examination with scleral indentation; B-scan ultrasound if the media are opaque.
- Treatment — surgical emergency (macula-on RRD is more urgent than macula-off).
- Pneumatic retinopexy — intraocular gas bubble plus cryo or laser; select cases (superior break, phakic eye).
- Scleral buckle — silicone band indents the sclera to appose RPE to retina; good for phakic eyes with peripheral breaks.
- Pars plana vitrectomy — for complex or posterior breaks, giant retinal tears, PVR. Endotamponade with gas (SF6, C3F8) or silicone oil.
Tractional retinal detachment (TRD)
Fibrovascular membrane traction lifts the retina without a full-thickness break.
- Causes — proliferative diabetic retinopathy (commonest), sickle cell retinopathy, retinopathy of prematurity, penetrating trauma, chronic uveitis.
- Treatment — pars plana vitrectomy with membrane peel; underlying disease control (glucose, PRP for PDR).
Exudative retinal detachment (ERD)
Sub-RPE or subretinal fluid without a break.
- Causes — Coats disease (idiopathic exudative retinal telangiectasia in young boys), choroidal melanoma or metastasis, uveitis (VKH syndrome — Vogt-Koyanagi-Harada), severe pre-eclampsia, malignant hypertension, central serous chorioretinopathy.
- Treatment — treat the underlying disease.
Posterior vitreous detachment (PVD)
An age-related liquefaction phenomenon (starts around 50 to 60 years; earlier in myopes). The vitreous cortex peels from the retina.
- Symptoms — new photopsia and a shower of floaters; a subjective Weiss ring (large translucent floater = detached glial ring around the optic disc).
- Fundoscopy — Weiss ring visible over the disc.
- Risk — 10 to 15 percent of symptomatic PVDs harbour a retinal tear.
- Management — dilated fundus examination with scleral indentation within one to two weeks; barrier laser retinopexy within 24 to 72 hours for any tear; observe with education if no tear.
Retinal tears vs holes
- Round atrophic hole — thinning; low risk of detachment; observe.
- Horseshoe (U-shaped) tear — vitreous traction at the flap; high risk of RRD; laser barrier urgently.
Vitreous haemorrhage
- Causes — proliferative diabetic retinopathy (commonest), retinal tear with bleeding, PVD, ocular trauma, retinal vein occlusion, Terson syndrome (subarachnoid haemorrhage).
- Symptoms — sudden painless vision loss, floaters, red haze.
- Fundoscopy — obscured red reflex; if partial, blood in the vitreous.
- Investigation — B-scan ultrasound when the fundus cannot be seen (rule out underlying RRD or mass).
- Management — observe for spontaneous clearance (1 to 3 months); vitrectomy if non-clearing or if there is a suspected retinal tear or detachment; PRP for underlying PDR.
Age-related macular degeneration (AMD)
The leading cause of central vision loss in over-65s.
Dry (non-neovascular) AMD — 85 to 90 percent
- Pathology — drusen (yellow lipid deposits under the RPE), pigmentary changes, geographic atrophy in advanced disease.
- Symptoms — gradual central blurring; near-vision loss.
- Management — AREDS2 vitamin combination (vitamin C, vitamin E, lutein, zeaxanthin, zinc, copper) slows progression in intermediate AMD. Smoking cessation.
Wet (neovascular) AMD — 10 to 15 percent
- Pathology — choroidal neovascularization (CNV) grows through Bruch membrane; subretinal fluid, haemorrhage, disciform scar.
- Symptoms — sudden central distortion (metamorphopsia detected on Amsler grid), central scotoma.
- Investigations — OCT (subretinal fluid, intraretinal cysts), fluorescein and indocyanine green angiography (CNV pattern).
- Treatment — intravitreal anti-VEGF — ranibizumab, aflibercept, bevacizumab (off-label but widely used in India for cost), brolucizumab, faricimab (dual anti-VEGF and anti-Ang2). Loading dose monthly for 3 months, then treat-and-extend at 4 to 12 week intervals.
Diabetic macular edema (DME)
- Pathology — inner blood-retinal barrier breakdown; central retinal thickening.
- Diagnosis — OCT measures central subfield thickness; fluorescein angiography shows focal leakage from microaneurysms.
- Treatment — intravitreal anti-VEGF first-line; intravitreal steroid (dexamethasone Ozurdex implant, fluocinolone Iluvien) in pseudophakic or non-responders; focal or grid laser for non-central DME.
Central serous chorioretinopathy (CSCR)
- Patient profile — young or middle-aged male, type A personality, stressed, exogenous or endogenous corticosteroid use.
- Pathology — RPE dysfunction leading to serous neurosensory retinal detachment at the posterior pole.
- Symptoms — subacute central blurring, metamorphopsia, micropsia, dyschromatopsia.
- Investigations — OCT (subretinal fluid), fluorescein angiography (classical smokestack or ink-blot leakage pattern).
- Management — observation (spontaneous resolution in 3 to 4 months in 80 to 90 percent); stop exogenous steroids; photodynamic therapy (PDT) with verteporfin for chronic or recurrent cases; micropulse laser; mineralocorticoid receptor antagonists (eplerenone) have limited evidence.
Retinitis pigmentosa (RP)
- Genetics — heterogeneous; autosomal recessive most common, autosomal dominant milder, X-linked (RPGR, RP2) most severe.
- Symptoms — night blindness (nyctalopia) first, followed by tunnel vision and eventual central loss.
- Signs — bone-spicule pigmentation in the mid-periphery, attenuated arterioles, waxy pale optic disc; ring scotoma on fields.
- ERG — diminished or extinguished rod response early; cone response fails later.
- Associations — Usher syndrome (RP plus sensorineural deafness), Bassen-Kornzweig syndrome (abetalipoproteinaemia), Refsum disease, Kearns-Sayre syndrome, Laurence-Moon-Bardet-Biedl syndrome.
- Management — no cure. Vitamin A palmitate slows progression in some patients. Genetic counselling. Voretigene neparvovec (Luxturna) — an AAV gene therapy for biallelic RPE65 mutation-associated Leber congenital amaurosis and RP; approved in the US and EU but very limited in India (cost prohibitive).
Retinal vascular occlusions
Central retinal artery occlusion (CRAO)
- Presentation — sudden painless profound monocular vision loss (count-fingers or worse).
- Signs — cherry-red spot at the fovea (intact choroidal circulation shows through thin fovea against oedematous pale peripapillary retina), pale infarcted retina, box-carring of retinal vessels, relative afferent pupillary defect (RAPD).
- Aetiology — carotid embolism (commonest), cardiac embolism, giant cell arteritis (in over-50s — must be excluded), hyperviscosity, vasculitis.
- Emergency management (within 6 hours):
- Ocular massage (10 to 15 seconds pressure then release, repeated).
- Anterior chamber paracentesis to acutely drop IOP.
- IV acetazolamide 500 mg plus topical timolol.
- High-FiO2 carbogen (95 percent O2 with 5 percent CO2) — maintains vasodilation.
- Consider intra-arterial thrombolysis at select stroke centres.
- Prognosis — poor; visually meaningful recovery unlikely beyond 6 to 12 hours.
- Workup — carotid Doppler, ECG, echocardiogram, ESR and CRP (temporal artery biopsy if GCA suspected — start high-dose prednisolone empirically without waiting for biopsy).
Central retinal vein occlusion (CRVO)
- Presentation — sudden or subacute painless vision loss (variable severity).
- Signs — blood-and-thunder fundus (dilated tortuous veins, four-quadrant retinal haemorrhages, cotton wool spots, disc oedema), macular oedema.
- Ischaemic vs non-ischaemic — RAPD, worse acuity and larger areas of capillary non-perfusion on fluorescein angiography define the ischaemic subtype (higher risk of neovascular glaucoma).
- Treatment — intravitreal anti-VEGF for macular oedema; panretinal photocoagulation if neovascular glaucoma develops (100-day glaucoma classically appears 3 months after ischaemic CRVO).
Branch retinal vein occlusion (BRVO)
- Presentation — sector visual field loss; painless.
- Signs — sectoral haemorrhages along an arteriovenous crossing (a hardened arteriole compresses the vein).
- Treatment — anti-VEGF for macular oedema; grid laser for persistent oedema; sector PRP if neovascularization develops.
Hypertensive retinopathy — Keith-Wagener-Barker
- Grade I — mild arteriolar narrowing, silver wiring.
- Grade II — AV nicking, focal arteriolar narrowing, copper wiring.
- Grade III — grade II plus flame haemorrhages, cotton wool spots, hard exudates.
- Grade IV — grade III plus papilloedema (malignant hypertension).
India-specific context
- Diabetic retinopathy — 16 to 19 percent prevalence in Indian diabetics; sight-threatening DR in 3 to 5 percent. National Programme for Prevention and Control of Non-Communicable Diseases (NPCDCS) and the NCVBDC-affiliated National Programme for Control of Blindness and Visual Impairment (NPCBVI) both incorporate DR screening.
- AMD — rising with aging demographics; late AMD prevalence around 2 percent in over-60s.
- Retinopathy of prematurity (ROP) — a leading cause of childhood blindness in India; national ROP screening under Rashtriya Bal Swasthya Karyakram (RBSK); screening required for all preterm infants born under 34 weeks or under 2000 g.
- Rural retinal service access — Aravind Eye Care System, LV Prasad Eye Institute (LVPEI), and Sankara Nethralaya run high-volume retinal surgery programmes with tele-ophthalmology outreach.
- Anti-VEGF cost barrier — bevacizumab (compounded) is a fraction of the cost of licensed ranibizumab or aflibercept and is widely used off-label in Indian public hospitals; recent supply and quality-assurance guidance from the Vitreo-Retinal Society of India.
NEET PG MCQ traps
- RRD symptoms — flashes, new floaters, curtain shadow. Not painful.
- Highest-risk RRD — high myopia, previous cataract surgery, lattice degeneration.
- Weiss ring — indicates PVD; 10 to 15 percent risk of associated retinal tear.
- Horseshoe tear — vitreous traction; barrier laser retinopexy urgently.
- TRD leading cause — proliferative diabetic retinopathy.
- Coats disease — young male, unilateral, exudative RD, retinal telangiectasia.
- Wet AMD — anti-VEGF (ranibizumab, aflibercept, bevacizumab, brolucizumab, faricimab).
- Dry AMD — AREDS2 vitamins in intermediate stage.
- Amsler grid — screens for metamorphopsia in AMD and macular disease.
- DME investigation of choice — OCT central subfield thickness.
- PDR treatment — panretinal photocoagulation; anti-VEGF adjunct.
- CRAO signs — cherry-red spot, pale retina, RAPD, box-carring.
- CRAO GCA — always rule out in over-50s; ESR, CRP; empirical steroid if suspected.
- CRVO fundus — blood-and-thunder appearance.
- 100-day glaucoma — neovascular glaucoma 3 months after ischaemic CRVO.
- CSCR — young stressed male, steroid link; smokestack leakage on FFA.
- Retinitis pigmentosa — night blindness first, bone-spicule pigmentation, ring scotoma, ERG diminished.
- Luxturna (voretigene) — AAV gene therapy for RPE65 mutations.
- Fovea — avascular; cone-rich; nourished by choroid.
- B-scan ultrasound — for opaque media (dense cataract, vitreous haemorrhage) to look for underlying detachment or mass.
Frequently asked questions
What is the difference between rhegmatogenous, tractional, and exudative retinal detachment?
Rhegmatogenous retinal detachment (RRD) is the commonest type — a full-thickness retinal break (tear or hole) lets liquefied vitreous seep into the subretinal space, separating the neurosensory retina from the retinal pigment epithelium. Symptoms are photopsia (flashes from vitreous traction), a shower of new floaters, and a curtain shadow spreading across the visual field. Risk factors are myopia, previous cataract surgery, ocular trauma, lattice degeneration, and posterior vitreous detachment. Tractional retinal detachment (TRD) occurs when fibrovascular membranes contract and pull the retina off — proliferative diabetic retinopathy is the leading cause, followed by sickle cell retinopathy and retinopathy of prematurity. Exudative retinal detachment (ERD) has no retinal break — fluid accumulates from the choroid because of inflammation, malignancy or hypertension (Coats disease, choroidal melanoma, VKH syndrome, severe pre-eclampsia).
Why is central retinal artery occlusion an ophthalmological emergency and how is it managed within the first six hours?
Central retinal artery occlusion (CRAO) presents as sudden, painless, profound monocular vision loss with a cherry-red spot at the fovea (thin foveal retina reveals the intact choroidal circulation under an infarcted, oedematous peripapillary retina) and a pale infarcted retina. Retinal neurons tolerate only about 90 to 100 minutes of complete ischaemia before irreversible damage; visually meaningful recovery is unlikely beyond 6 to 12 hours but attempts are still made within the first 24 hours. Emergency measures within six hours include ocular massage (digital pressure for 10 to 15 seconds then release, repeated) to dislodge an embolus, anterior chamber paracentesis to drop intraocular pressure and shift the block downstream, intravenous acetazolamide 500 mg plus topical timolol, high-FiO2 carbogen (95 percent O2 with 5 percent CO2) to maintain vasodilation, and consideration of intra-arterial thrombolysis at select stroke centres. Every CRAO also needs an urgent stroke workup — carotid Doppler, ECG, echocardiogram, ESR and CRP for giant cell arteritis in over-50s (temporal artery biopsy if suspected).
How do you distinguish wet from dry age-related macular degeneration and what is the standard treatment for each?
Age-related macular degeneration is the leading cause of central vision loss in over-65s. Dry (non-neovascular) AMD accounts for 85 to 90 percent of cases and progresses slowly through drusen (yellow deposits under the RPE), pigmentary changes, and eventually geographic atrophy of the RPE. There is no proven curative therapy; AREDS2 vitamin combination (vitamin C, vitamin E, lutein, zeaxanthin, zinc, copper) slows progression in intermediate stages. Wet (neovascular) AMD, 10 to 15 percent of cases, is defined by choroidal neovascularization (CNV) growing through Bruch membrane into the subretinal space with leakage, haemorrhage and eventual disciform scarring. Presentation is sudden or subacute central distortion (metamorphopsia detected on the Amsler grid) and loss. OCT shows subretinal fluid or intraretinal cysts; fluorescein angiography confirms CNV. Treatment is intravitreal anti-VEGF injection — ranibizumab, aflibercept, bevacizumab (off-label but widely used in India for cost), brolucizumab or faricimab — every 4 to 12 weeks in a treat-and-extend regimen. Early treatment preserves reading vision.
What is the significance of a Weiss ring and how should a fresh symptomatic posterior vitreous detachment be evaluated?
A Weiss ring is a ring-shaped floater visible on fundoscopy or reported subjectively as a large translucent floater — it corresponds to the detached, previously attached glial ring around the optic disc after the vitreous cortex peels off. Its presence confirms a posterior vitreous detachment (PVD). PVD is an age-related liquefaction phenomenon (starts around 50 to 60 years, earlier in myopes). Every acutely symptomatic PVD — new photopsia, showers of new floaters, or a subjective Weiss ring — needs a dilated fundus examination with scleral indentation within one to two weeks because 10 to 15 percent of symptomatic PVDs harbour a retinal tear (horseshoe or U-shaped tear from vitreous traction at the vitreous base). A discovered tear needs urgent barrier laser retinopexy within 24 to 72 hours. A PVD without a tear can be observed with patient counselling — return immediately if new symptoms appear.
How does diabetic macular edema differ from proliferative diabetic retinopathy in treatment approach?
Diabetic macular edema (DME) is thickening of the central macula from breakdown of the inner blood-retinal barrier — it causes central vision loss at any stage of diabetic retinopathy (non-proliferative or proliferative). Diagnosis is by OCT (measures central retinal thickness) plus clinical or angiographic findings (hard exudates, microaneurysms, focal leakage on fluorescein angiography). First-line treatment is intravitreal anti-VEGF injection (ranibizumab, aflibercept, faricimab, bevacizumab); intravitreal steroid (dexamethasone implant, fluocinolone) is used in pseudophakic patients or non-responders; focal or grid laser photocoagulation is reserved for select non-central DME. Proliferative diabetic retinopathy (PDR) is a separate problem — abnormal neovascularization on the disc (NVD) or elsewhere (NVE) driven by widespread retinal ischaemia; complications are vitreous haemorrhage and tractional retinal detachment. The definitive treatment for PDR is panretinal photocoagulation (PRP) — 1500 to 2000 burns in scattered pattern in the mid-periphery — which regresses neovascularization by ablating the ischaemic retina. Anti-VEGF is an adjunct for PDR (regresses NV faster than laser alone) and mandatory when PDR is combined with DME. Vitrectomy is needed for non-clearing vitreous haemorrhage or tractional retinal detachment.
This content is for educational purposes for NEET PG exam preparation. It is not a substitute for professional medical advice, diagnosis, or treatment. Clinical information has been reviewed by qualified medical professionals.
Written by: NEETPGAI Editorial Team
Reviewed by: Pending SME Review
Last reviewed: September 2026
